* osd pool erasure code stripe width
@ 2015-06-19 20:11 Deneau, Tom
2015-06-19 22:47 ` Loic Dachary
0 siblings, 1 reply; 4+ messages in thread
From: Deneau, Tom @ 2015-06-19 20:11 UTC (permalink / raw)
To: ceph-devel
I am trying to understand the use of "osd pool erasure code stripe width"
For example, I have a single-node system with a k=2,m=1 ec pool
and I write a single 40M object to this pool using rados bench.
But when I look on the disk, I still see only the 3 20M pieces for this object.
Where does the striping get used?
-- Tom Deneau, AMD
Description:
Sets the desired size, in bytes, of an object stripe on every erasure coded pools. Every object if size S will be stored as N stripes and each stripe will be encoded/decoded individually.
Type:
Unsigned 32-bit Integer
Default:
4096
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: osd pool erasure code stripe width
2015-06-19 20:11 osd pool erasure code stripe width Deneau, Tom
@ 2015-06-19 22:47 ` Loic Dachary
2015-06-20 1:18 ` Deneau, Tom
0 siblings, 1 reply; 4+ messages in thread
From: Loic Dachary @ 2015-06-19 22:47 UTC (permalink / raw)
To: Deneau, Tom, ceph-devel
[-- Attachment #1: Type: text/plain, Size: 959 bytes --]
Hi Tom,
A stripe width of 4KB (the default) means the object is encoded 4KB at a time. It does not show in the file written to disk.
Cheers
On 19/06/2015 22:11, Deneau, Tom wrote:
> I am trying to understand the use of "osd pool erasure code stripe width"
> For example, I have a single-node system with a k=2,m=1 ec pool
> and I write a single 40M object to this pool using rados bench.
> But when I look on the disk, I still see only the 3 20M pieces for this object.
> Where does the striping get used?
>
> -- Tom Deneau, AMD
>
>
> Description:
> Sets the desired size, in bytes, of an object stripe on every erasure coded pools. Every object if size S will be stored as N stripes and each stripe will be encoded/decoded individually.
> Type:
> Unsigned 32-bit Integer
> Default:
> 4096
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
>
--
Loïc Dachary, Artisan Logiciel Libre
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 198 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
* RE: osd pool erasure code stripe width
2015-06-19 22:47 ` Loic Dachary
@ 2015-06-20 1:18 ` Deneau, Tom
2015-06-20 6:27 ` Loic Dachary
0 siblings, 1 reply; 4+ messages in thread
From: Deneau, Tom @ 2015-06-20 1:18 UTC (permalink / raw)
To: Loic Dachary, ceph-devel
So if I am looking at the performance of a system with
ceph_erasure_code_benchmark, does this mean I should concentrate
on the performance with --size 4096 (or whatever stripe width my
ec pools are going to use)?
-- Tom
> -----Original Message-----
> From: Loic Dachary [mailto:loic@dachary.org]
> Sent: Friday, June 19, 2015 5:47 PM
> To: Deneau, Tom; ceph-devel
> Subject: Re: osd pool erasure code stripe width
>
> Hi Tom,
>
> A stripe width of 4KB (the default) means the object is encoded 4KB at a
> time. It does not show in the file written to disk.
>
> Cheers
>
> On 19/06/2015 22:11, Deneau, Tom wrote:
> > I am trying to understand the use of "osd pool erasure code stripe width"
> > For example, I have a single-node system with a k=2,m=1 ec pool and I
> > write a single 40M object to this pool using rados bench.
> > But when I look on the disk, I still see only the 3 20M pieces for this
> object.
> > Where does the striping get used?
> >
> > -- Tom Deneau, AMD
> >
> >
> > Description:
> > Sets the desired size, in bytes, of an object stripe on every erasure coded
> pools. Every object if size S will be stored as N stripes and each stripe
> will be encoded/decoded individually.
> > Type:
> > Unsigned 32-bit Integer
> > Default:
> > 4096
> >
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe ceph-devel"
> > in
> >
>
> --
> Loïc Dachary, Artisan Logiciel Libre
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: osd pool erasure code stripe width
2015-06-20 1:18 ` Deneau, Tom
@ 2015-06-20 6:27 ` Loic Dachary
0 siblings, 0 replies; 4+ messages in thread
From: Loic Dachary @ 2015-06-20 6:27 UTC (permalink / raw)
To: Deneau, Tom, ceph-devel
[-- Attachment #1: Type: text/plain, Size: 1756 bytes --]
Hi Tom,
On 20/06/2015 03:18, Deneau, Tom wrote:
> So if I am looking at the performance of a system with
> ceph_erasure_code_benchmark, does this mean I should concentrate
> on the performance with --size 4096 (or whatever stripe width my
> ec pools are going to use)?
Yes. But the erasure code plugin encoding speed is not the only factor. You probably want to try a rados bench instead to get more realistic numbers.
Cheers
>
> -- Tom
>
>> -----Original Message-----
>> From: Loic Dachary [mailto:loic@dachary.org]
>> Sent: Friday, June 19, 2015 5:47 PM
>> To: Deneau, Tom; ceph-devel
>> Subject: Re: osd pool erasure code stripe width
>>
>> Hi Tom,
>>
>> A stripe width of 4KB (the default) means the object is encoded 4KB at a
>> time. It does not show in the file written to disk.
>>
>> Cheers
>>
>> On 19/06/2015 22:11, Deneau, Tom wrote:
>>> I am trying to understand the use of "osd pool erasure code stripe width"
>>> For example, I have a single-node system with a k=2,m=1 ec pool and I
>>> write a single 40M object to this pool using rados bench.
>>> But when I look on the disk, I still see only the 3 20M pieces for this
>> object.
>>> Where does the striping get used?
>>>
>>> -- Tom Deneau, AMD
>>>
>>>
>>> Description:
>>> Sets the desired size, in bytes, of an object stripe on every erasure coded
>> pools. Every object if size S will be stored as N stripes and each stripe
>> will be encoded/decoded individually.
>>> Type:
>>> Unsigned 32-bit Integer
>>> Default:
>>> 4096
>>>
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe ceph-devel"
>>> in
>>>
>>
>> --
>> Loïc Dachary, Artisan Logiciel Libre
>
--
Loïc Dachary, Artisan Logiciel Libre
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 198 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-06-20 6:27 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-06-19 20:11 osd pool erasure code stripe width Deneau, Tom
2015-06-19 22:47 ` Loic Dachary
2015-06-20 1:18 ` Deneau, Tom
2015-06-20 6:27 ` Loic Dachary
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.